1. Field of the Invention
The invention relates to the field of antenna. More specifically, a wide band antenna is provided that has the characteristics of compact size, simple structure and easy fabrication and is particularly well-suited for operating at ultra wide band communication frequency range.
2. The Related Art
The ultra-wide band (UWB) communication is a wireless communication method, which was first developed by the United States Department of Defense in the 1960's and used for military purposes. The UWB communication has a wide frequency range (3.1 to 10.6 gigahertz), a low power consumption (−40 dBm/MHz), and a fast transmission speed. The UWB communication is expected to be used extensively in various systems, such as personal communication networks or home networks connecting personal computers (PC), television receivers (TV), personal digital assistants (PDA), digital versatile discs (DVD), digital cameras, and printers.
Due to advantages of the UWB communication, development of a wide band antenna with the characteristics of compact size, simple structure and easy fabrication is one of design project nowadays. Taiwan Patent Application Serial Number 095216657 is disclosed a wide band antenna. The wide band antenna has a radiating body and an impedance transfer arranged at one surface of a printed circuit board. The radiating body is consist of a funnel portion and a rectangle portion. The impedance transfer connects the funnel portion and a feeding cable. A ground portion is arranged at other surface of the printed circuit board.
The range of resonance frequency of the wide band antenna is tunable by changing dimension of the funnel portion of the radiating body. The impedance of the wide band antenna is tunable by adjusting impedance value of the impedance transfer. Tuning dimension of the funnel portion of the radiating body and impedance value of the impedance transfer to obtain preferred range of resonance frequency and impedance is complex for design process.